The present invention relates to an injection valve including a perforated disk having a first surface, a second surface, and at least one spray hole, the spray hole being punched in a direction from the first surface to the second surface.
German Published Patent Application No. 40 26 721 ("the '721 application") discusses an injection valve which has a perforated disk downstream of its valve seat surface. The perforated disk of the '721 application has a plurality of spray holes, through which a medium such as fuel can pass. The spray holes in the perforated disk are made by erosion.
Using perforated disks, with spray holes made by punching, on injection valves is known. For example, cup-shaped perforated disks are made from a thin sheet and have a tensile strength of 400 to 600N/mm.sup.2, depending on the material. When the spray holes are punched into the perforated disk, a punching draw-in is formed at the edge of the spray hole in a first surface (i.e., the surface of the perforated disk struck by the punch), and a protrusion, in the form of a burr, is formed at the edge of the hole in a second surface (i.e., the surface of perforated disk from which the punch emerges). Unfortunately, if the number of punching operations is large, it is impossible to keep these disadvantageous burrs constant and, as a result, relatively large scatter may occur in the flow and in the spray angle. In mass production, minimizing this scatter is desired. To minimize this disadvantageous scatter, the punching burrs can be ground off. However, the grinding process increases the cost of manufacturing the perforated disk. Accordingly, a process for producing perforated disks without burred holes, which does not require a separate grinding step, is needed.